The present invention relates generally to automotive lamp socket designs. More specifically, the present invention is an auto lamp socket construction incorporating a wire inlet and silicone sealant, which, when combined with ultrasonic welding of an elastomeric housing and a back cap element, exhibits improved sealing characteristics at the interface between the lamp socket and lighting assembly, as well as between the wires and the lamp socket. The present invention also provides an improved lamp socket design with a reduced part count.
Existing technologies for automotive lamps consist of assemblies of plastic, metal and elastomeric type materials. The lamp socket is connected to the vehicle electrical system, via electrical conductors (i.e., wire and terminals) and a main requirement of the lamp construction is the ability to seal out moisture, such being a common environmental consideration in automotive application.
U.S. Pat. No. 4,940,422, issued to Forish et al., discloses an automotive lamp socket assembly having a housing, contact insert and body. The contact insert is captured in a cavity defined within the housing by the body, which is in turn welded to the housing. Lugs on the body secure the assembly to a panel. A seal is placed between a flange on the housing and the panel to seal the assembly to a panel. Contacts are retained in the contact insert by engagement of U-shaped portions in slots of the contact inserts. Blade terminals are inserted through windows in the housing, contact insert, and contacts to interlock the terminals with the contacts and to keep the contacts secured in their positions. A socket connector is sealingly secured to the housing and prevents moisture from entering the housing. Reference is also made to U.S. Pat. Nos. 4,958,429 and 5,000,702, both claiming priority from the U.S. Pat. No. 4,940,422 patent, and which illustrate additional variations of this design.
U.S. Pat. No. 5,087,213, issued to Drapcho, teaches a lamp socket for a lamp bulb having a contact base that includes a right angle/single piece plastic socket portion with a tubular part into which a metallic ring-like member is inserted. The ringlike member serves the dual purpose of a lamp bulb retainer as well as the ground contact for the lamp bulb. It is also noted that Drapcho teaches the use of a seal independent of the socket assembly.
Finally, U.S. Pat. No. 4,573,754, issued to Hill, teaches a lamp assembly for automotive tail lamps and which includes a base member constructed of a relatively soft elastomeric material, a connector of a relatively hard material adapted to be sealingly but reasonably plugged into a cavity opening in one face of the base member, and a bulb socket of a relatively hard material adapted to be sealingly but reasonably plugged into another cavity in the base opening in a face which is normal to the face in which the connector is received. Conductors extend in parallel fashion in the base member between the socket cavity and the connector cavity. The conductors make electrical connection at their one ends with contacts on the lower end of the socket and pass sealingly through a partition separating the two cavities where their other ends make electrical contact with terminals carried by the connector and so that the connector, base and socket provide a measure of moisture resistance to the lamp assembly.
The present invention is a lamp assembly for use with a vehicle""s electrical system and which is an improvement over the prior art in that it provides an improved assembly for sealing the interfaces between the vehicle""s lamp socket and lighting assembly, as well as between the interface between the terminal wires of the electrical system and the lamp socket. The lamp assembly of the present invention further provides an improved sealing construction with the added feature of substantially reduced part content.
The lamp assembly includes a main elastomeric housing having a socket for receiving a bulb, a front seal encircling an exterior surface of the socket, and a first plurality of sealing ridges extending along an open facing side. Laid within the sealing ridges are wire insulating portions of a plurality of terminals belonging to the vehicle electrical system. Each of the terminals further includes an end connector portion, secured to an end of an associated wire insulating portion, and communicating with the bulb socket upon the terminals being located within the main housing.
A back cap, likewise constructed of a plasticized and elastomeric material, matingly aligns over the open facing side of the main housing. The back cap includes an opposingly facing side with a second plurality of sealing ridges defined therein, and which aligns with the first plurality of sealing ridges to sandwich therebetween the wire insulating portions of the terminals laid within the main housing.
An inlet seal is constructed of a specified three-dimensional shape and which is seatingly received between aligning recesses defined between the main housing and the back cap in proximity to the first and second pluralities of sealing ridges. Wire receiving apertures extend through the inlet seal and communicate with a selected edge location of the seal by split seal edges defined within the seal. The wire insulating portion of each terminal is depressingly engaged through a split seal and into an associated receiving aperture. In a final assembly, step, an ultrasonic or vibration welding operation is performed for sealingly engaging the back cap to the main elastomeric housing.
In a preferred embodiment, pluralities of three sealing ridges are defined, respectively, along each of the main housing and the back cap. The inlet seal further includes first, second and third wire receiving apertures for receiving, respectively, specified locations of the wire insulating portions corresponding to the first, second and third terminals. Both the front seal and the terminal inlet seal are further preferably constructed of a silicone material and so as to provide the necessary characteristics of elasticity and water-tight sealability.